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Old Oct 16, 2012, 12:51 AM
klaw81 is offline
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Australia, QLD, Toowoomba
Joined Jul 2012
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The Bixler build and maiden flight

There are heaps of threads about how to put a Bixler together, and frankly it's so easy that there's not much more to say. But I've finished building mine, and I'm pretty happy with the result.

I've made a number of modifications to the stock plane, in an effort to make it more suitable for FPV. Most of these modifications have been prompted by other threads on this forum about the Bixler - thanks for the assistance and the valuable information about what works.

My whole fuselage was joined together with hot-melt glue. I am hoping this will allow me to open it up again, should the need arise. The whole process only took 10 minutes or so. I also removed some of the more garish decals, and did a paint job to make the plane a little more distinctive. The tail and undersides of the wings have been repainted, and I will probably add some aluminium foil to the tops of the wings as well. This simple trick reflects the sunlight, even on the greyest of days, and is very helpful with long-distance orientation (and lost planes in long grass).

Here's a list of my mods to the airframe:

1. Remove weights from the nose. This is a simple operation, but they're very well stuck with big globs of hot glue. They took quite a lot of force to remove.

2. Additional reinforcing in various locations:
- a 3mm hollow carbon rod about 550mm long in the base of the tail boom fits perfectly into the groove provided and stiffens the whole structure nicely.
- a 2mm solid carbon rod about 150mm long embedded in the underside of the horizontal stabiliser, just forward of the elevator and glued flush.
- 2 x 2mm bamboo skewers embedded in the vertical stabiliser. The base of the skewers are embedded in the tail boom.
- a 6mm x 0.5mm carbon strip x 500 long, embedded in the underside of each wing. This overlaps with the main wing spar by 200mm or so, and makes the ends of the wings less floppy.

3. I swapped the elevator and rudder servos for new HXT900 servos. I considered moving them to the rear of the plane, but found that I had plenty of room in the fuselage without this extra task. If I end up needing the extra space, I can always do this later.

4. Additional ventilation for the battery, ESC and motor:
- I used a hot metal rod to melt vents into both sides of the nose, and create a similar vent at the top of the tail boom, below the motor. These allow air to blow over the ESC and battery.
- I trimmed around the motor and motor vent to allow more air to flow past the motor and help it to run cool.

5. Velcro wing joiners. I am still experimenting with these, trying to avoid external joiners or hooks - so far it's working while the airframe is fresh and new, but I may have to resort to more drastic measures after a few heavy landings.

6. Additional magnets on the canopy - the stock arrangement has magnets in the fuse and only metal strips (not magnets) in the canopy itself. I have replaced all the magnets with new rare-earth items, and the canopy now clips down very firmly.

7. I replaced the standard prop with a 6x4E prop. The stock prop in my kit was a very low-quality affair, with casting dags around the centre boss and trailing edge of the blades. It was also rather poorly balanced, and way too flexy for my liking...so I threw it away. The 6x4E prop was much stiffer and better-constructed, and I just had to carefully ream out the centre to suit the standard Bixler prop adaptor.

8. I have installed flaps to assist with slower landings, and in areas where I don't have much runway. I cut away the rear of the wing, inboard of the ailerons, bevelled the foam, inserted plastic hinges and cut in servo recesses into the underside of the wing.

9. I installed a 'lost-plane beeper' in the Bixler, and glued it to the outside of the fuselage under the wing. It's actuated from the Gear switch on my radio, or if the Rx loses signal. Hopefully, it will help with finding the plane if it goes down in long grass or scrub.

The maiden flight went beautifully. It was perhaps a little too windy for prudent pilots, but I was sick of waiting for the right conditions. Thankfully, the Bixler is so easy to fly that I didn't really have to try; half-throttle, a light toss into the wind and it fly away with very little input. It just has a tendency to dip the nose during launch (due to the motor angle?) but is otherwise very simple.

I had forgotten how relaxing a plane like this is to fly - it's really quite capable of looking after itself. It has plenty of power for steep climbs to a safe altitude, it handles steep banks with only a small touch of rudder required, and it glides very nicely. In fact, it glides so well that I had trouble landing it - I needed 3 passes to get the speed correct and set it down.

I had disabled the flaps for the maiden flight, in case they were going to cause trouble. But since it went so well, they were quickly reconnected. I programmed them to be controlled from the 3-postion switch on my 9X, so I can engage them in two stages, and I've programmed a mix into the elevator so that the plane remains relatively level when the flaps are down. They're gratifyingly effective - even when carrying a fair bit of ballast, you can slow right down and the plane will just slowly descend while maintaining a nose-up attitude. I am extremely pleased with this mod, it was totally worthwhile - plus it's lots of fun to play around with.

I'm absolutely thrilled with the Bixler - it's exactly the training platform I hoped it would be. It's a well-built craft with excellent flight characteristics and it's a doddle to fly. Money well spent, I think.

My next project was to build an FPV platform on the front, so I could mount my camera. More on this next entry.....
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